E90 M3 - DSC unit failure

[NIIKME]

I previously posted due to TPMS / DSC issues but I cannot find the thread now. The problem continues and I am interested to see if this is a unique issue to me or if anyone can offer advice -

My 2008 Car has been into the dealers twice now to have its software reset, and on the first visit the steering angle sensor was also recalibrated. Upon leaving the car drives absolutely fine for a couple of days and then a series of lights come on in sequence - TPMS failure, followed by DSC inactive. There's no way to reset it without a visit to the dealers again! Argh!

So........on the 3rd time I thought I would try a local indy for a second opinion. They also find nothing mechanically wrong with the car, but "suspect" that the DSC unit is broken because, if I understand them right, there is no single fault code to suggest that one of the sensors in either the wheels or steering column are faulty. The problem I have is its going to be a big bill to replace it without me or them knowing for 100% certainty that it will cure the problem.

Meanwhile I've had battery issues for a little over a year. Initially cured by a battery conditioner but I'm too lazy to plug it in every day. The battery is low (no question) so I will get that changed now to see what happens. I've heard of low batterys causing all sorts of weird and wonderful issues on these cars so I just wonder if it might solve the mystery?

I'll report back over coming weeks but has anyone else suffered TPMS / DSC issues like this?

[Schermerhorn]

Battery change could be the easist, cheapest and quickest fix.

[NIIKME]

it could also not, but its £250 that needs to be spent at some stage so its booked in.

[-Z-]

• Cough* buy BMW monthly warranty, wait 30 days and claim? Not that I would ethically endorse such a plan

[helix402]

If the steering angle sensor is faulty recalibration may be a short term fix. If the fault reoccurs replacement is necessary.

[helix402]

If the steering angle sensor is faulty recalibration may be a short term fix. If the fault reoccurs replacement is necessary.

[NIIKME]

Both garages are telling me the codes don't point to any one sensor as being faulty. It's a strange mix of codes apparently.

[philmots]

I'd wager the battery will sort it..

If you diy it, it's essential you get it programmed after. Basically telling the car it's got a new battery.

[t8cmf]

philmots said:

I'd wager the battery will sort it..

If you diy it, it's essential you get it programmed after. Basically telling the car it's got a new battery.

+1

This is definitely your first course of action.

I have an E92 M3 and know that these cars are incredibly sensitive to low voltages. They really spaz out when batteries start to fail. I know people who have sourced batteries and got the coding done for about £120 so do not pay £250. Get a Ctek MXS 5.0 when you get your new battery as it will ensure it stays healthier for longer.

[NIIKME]

Ok, lets touch wood the battery cures the car then! I'm having a local garage do it next week because of the reset required. I have a Ctek but because of storing the car under a car port its a bit of a pain to use. Great piece of kit though!

[NIIKME]

Update:
So the new battery was in place for one week and life was all good until.......the dreaded light sequence came on and the car is now in its familiar state of TPMS failure, system error, no DSC - requiring a trip to the dealers for a software reset! Oh joy! I've got used to driving it with no DSC now
Any ideas?

[E30M3SE]

Has the alternator charge level been checked?

[essayer]

E30M3SE said:

Has the alternator charge level been checked?

I wonder this too. Remember that when it's being updated at the dealers it will be kept on a charger all the time so if there are any alternator issues you might not notice until after a few days.

[NIIKME]

I think I recall them saying one of the many fault codes relates to the alternator. How would they check it, or is it simply a case of me asking them to check the alternator? The basic challenge here is isolating the root cause.

[E30M3SE]

As a preliminary check that you can do follow the instructions in this video,

https://www.youtube.com/watch?feature=player_embed...

you're looking for around 14V at idle speed with all electrical equipment turned off.

[cammy71]

My 07 E92 M3 had a similar issue but was not the battery. Out of the blue 3 error messages all pinged on at once - tyre pressure monitor failure, DSC failure, engine problem reduced power. Drove home left overnight and started with no errors. Went to mums for an hour came out and same 3 messages came on. Into dealers and it was the throttle actuators, both banks - £1800 later, problem solved. Google it and it seems to be a not uncommon issue. Out of warranty but tried, BMW UK not interested, but local dealer gave discount due to previous custom (£1800 is post discount!). Worth a try.

[NIIKME]

Chaps, thanks for the responses and just to keep this updated for any future owners..
I have since found time to get back into the garage and after a quick plug into the autologic unit the Steering Angle Sensor appears to be completely dead now. Specifically the fault is saying the sensor is not registered to the car! aving had this sensor recalibrated twice recently it makes sense that it maybe have been slowly dying or something over the last 6 mths....
It goes back in on the 28th for a full diadnosis. I have read many a thread about this sensor causing problems on the E46, and less so but still issues on the E90/2/3 so hopefully its this thats causing all the issues.
Will post back results!